To salvage the submarine, they built a salvage ship which looked as though it was a deep sea mining vessel

Inside it was a revolutionary "moon pool", a gigantic opening big enough to hold (and hide) the Russian submarine once it was cherry-picked by a set of giant, retractable metal claws.

The Russians tried and failed to locate the submerged sub but the Americans succeeded after its underwater listening posts picked up the sound of its explosion.
Hughes, immortalised by Leonardo DiCaprio in The Aviator, was approached by the CIA through his longtime business partner David Charnay in 1972.

For American spooks Hughes - a reclusive, extravagant billionaire with a penchant for adventure - was the perfect cover for Project Azorian.